The atmosphere distorts the spectrum of remotely sensed data, negatively affecting all forms of investigating Earth's surface. To gather reliable data, it is vital that atmospheric corrections are accurate. The current state of the field of atmospheric correction does not account well for the benefits and costs of different correction algorithms. Ground spectral data are required to evaluate these algorithms better. This dissertation explores using cameras as radiometers as a means of gathering ground spectral data. I introduce techniques to implement a camera systems for atmospheric correction using off the shelf parts. To aid the design of future camera systems for radiometric correction, methods for estimating the system error prior to construction, calibration and testing of the resulting camera system are explored. Simulations are used to investigate the relationship between the reflectance accuracy of the camera system and the quality of atmospheric correction. In the design phase, read noise and filter choice are found to be the strongest sources of system error. I explain the calibration methods for the camera system, showing the problems of pixel to angle calibration, and adapting the web camera for scientific work. The camera system is tested in the field to estimate its ability to recover directional reflectance from BRF data. I estimate the error in the system due to the experimental set up, then explore how the system error changes with different cameras, environmental set-ups and inversions. With these experiments, I learn about the importance of the dynamic range of the camera, and the input ranges used for the PROSAIL inversion. Evidence that the camera can perform within the specification set for ELM correction in this dissertation is evaluated. The analysis is concluded by simulating an ELM correction of a scene using various numbers of calibration targets, and levels of system error, to find the number of cameras needed for a full-scale implementation.

The collector of an oscillating water column system (OWC) for wave energy utilization requires a bidirectional turbine that copes with pneumatic power while providing specified impedance or, in terms of an OWC designer, “damping”. Damping is realized by keeping to a specific flow rate through the turbine at a given pressure head due to the individual performance characteristic of the turbine. With the number of turbine designs increasing designers of OWC systems are facing more options to select and dimension a bidirectional turbine. Energy yield, size and hence cost of the turbine and electric generator, operational behaviour, envisaged control strategy and noise emitted by the turbine are possible criteria for selection. The primary objective of this paper is to describe a simple procedure for making a first choice of a turbine for a particular OWC application. Here we confine ourselves to a family of reaction type of turbines (axial-flow Wells and mixed-flow turbines by Moisel) with their approximately linear pressure head/volume flow rate characteristics. Starting point is the set of non-dimensional steady-state characteristics of each turbine in the family. Utilizing standard scaling laws and a very simple time domain model for the cyclic turbine operation (i.e. based one single sea state and turbine operation assumed to be fixed rotational speed), first estimates of turbine size and rotor speed, number for stages or flows, and performance curves can be determined. The resulting turbine may also serve as a starting configuration for a refined analysis, e.g. the optimization of the turbine and the complete OWC system, utilizing more complex stochastic models. Three case studies illustrate the application of the method: selection and scaling of turbines, effect of collector parameters, turbines in series and parallel.

Anxiety is the most common mental health diagnosis for adolescents. Among important etiological factors are parent anxiety and parenting behavior, which can increase anxiety in adolescents. Adolescent anxiety can also act as a source of stress for parents that then increases parent anxiety and negative parenting behaviors. Using the Family Stress Model, this study aims to examine the longitudinal and bidirectional relationship between parent and adolescent anxiety with parental psychological control acting as a mediator. Structural equation modeling was used to examine these relationships across five waves of data for 457 families. Adolescents (51.86% female, mean age 13.34 at wave one) and their parents (352 fathers and 457 mothers) participated in this study. While results did not fully support the hypotheses, interesting relationships among study variables indicated the importance of adolescent gender and development when studying the impact of parents and parenting on anxiety. Implications for research and clinical practice are discussed.

An experimental study was performed on a low frequency transcritical thermoacoustic engine developed at Maurice J. Zucrow Laboratories. The goal of the experiment was to characterize the effects of engine geometry on the thermoacoustic production of the working fluid and to use insights gained to design a power extraction device for the transcritical thermoacoustic engine. The effects of geometry were investigated by parametrically varying the length of the resonator and the diameter of the resonator and measuring the pressure amplitude and frequency of thermoacoustic instabilities developed at varying ∆T and one bulk pressure of P Pcr = 1.1. It was found that increasing resonator length increases pres?sure amplitude, decreases frequency, and increases acoustic power developed. Increasing resonator diameter decreases pressure amplitude, increases frequency, and increases acoustic power developed. It was also experimentally proven that coiled tube sections in the res?onator attenuate the thermoacoustic pressure wave. After testing, the knowledge gained was applied to the design of a bidirectional impulse turbine for eventual integration into a scaled-up version of the current thermoacoustic engine to be used to extract power from the thermoacoustic instabilities developed in the rig.

LoRaWAN is one of the most adopted low-power wide-area networks, which use theproprietary LoRa modulation developed by Semtech to provide high sensitivity at lowdata rates for long ranges. LoRaWAN providing coverage using single-hop gatewaysto thousands of end-devices (sensors) running on batteries. Each gateway requires aconnection to the internet or a private network (Ethernet, 3G/4G, Wifi) to communicatewith the network server. In obstructed areas, with mountains, foliage, or simplyvast areas, multiple gateways are required to provide coverage for the end-devices.Internet/mobile coverage might be missing in some areas. Which quickly brings upthe cost of internet connection in these areas, unless a solution is developed that routesmessages between the gateways using the existing LoRa radio communication standard.Thus reducing required internet connections while providing coverage. This solutionwas developed and evaluated, with a focus on supporting LoRaWAN deviceswith bidirectional capabilities, following the regional regulations, and providing arouting protocol that minimizes the extra data that comes with routing messages overa network. Experiments of three gateways showed that the solution provides a functioningrouting protocol, with as low as 3 extra bytes for routing. While fast enough toprovide bidirectional communication support for end-devices located farthest awayfrom the gateway with the server connection.

In the development of autonomous vehicles, replacing the driver and its perceptive abilities is one of many technical challenges. As a part in solving these challenges, Light Detection And Ranging (LiDAR) is a promising technology. In short, LiDAR works by using lasers to detect objects in its vicinity by detecting the light that reflects on them. With knowledge of the reflective properties of an object, a prediction can be made regarding whether a certain LiDAR unit will be able to detect the object or not. When making this prediction, the common description of reflectance is often insufficient. Instead, a more complete description is given by the Bidirectional Reflectance Distribution Function (BRDF) of a surface, which describes reflection on the surface while taking the incident and reflected direction into consideration. In this thesis, an experimental setup was built with the capabilities of measuring the BRDF while taking incident and reflected polarization into account. Program software was written in Python and integrated with the hardware, providing a user interface for simple control of the setup. The BRDF was measured on a total of 6 samples; 2 reference samples and 4 samples taken from the hood of 4 different cars. Conclusively, the setup provided useful information about the reflective and polarization properties of the samples. These measurements can help in predicting whether or not a surface can be detected by a given LiDAR unit, and can also be helpful when designing new LiDAR units by providing useful information about the surfaces they are required to detect.

No description available.

This study examined interference between three non-speech tasks and concurrent speech performance. The non-speech activity consisted of computer-based mathematical, language, and visuospatial tasks. The speech tasks included a procedural discourse monologue and a conversation. Participants included 60 adults in two age groups with 30 participants each. The younger adults were aged from 18 to 30 years and older adults from 55 to 82 years. Each participant completed the non-speech tasks in isolation, the speech tasks in isolation, and then each of the speech tasks concurrently with each of the three non-speech tasks. Speech acoustic measures included the mean and standard deviation of intensity and fundamental frequency as indicators of prosody, speaking time ratio to reflect speaking versus pausing time, and speech rate. Non-speech measures included total responses, correct responses, and accuracy. Statistical analysis revealed significant divided attention effects on speech, with increases in fundamental frequency and decreases in speaking time ratio, speech rate, and intensity. Performance on all non-speech tasks was negatively impacted by speech, as there was a significant decrease in total responses and total correct responses overall. There was a significant age effect for intensity and fundamental frequency variability, in that the younger group had less prosodic variation compared to the older group. The present findings provide some evidence that the effects of divided attention increase with age, as older adults gave fewer responses than younger adults overall. However, results indicate older adults prioritize accuracy over speed compared to younger adults. These findings suggest that bidirectional interference occurs between speech and mathematical, language, and visuospatial tasks. The results expand what is known about bidirectional interference between speech and other concurrent tasks, as well as the effects of age on divided attention.

Quantifying the appearance of a surface is an important aspect in quality control. Becauseobjects at room temperature emit negligible amounts of radiation into the visible spectrum, aspectsof their appearance may be quantified using reflected light. Therefore, the appearance of opaquesurfaces may be quantified using measurements of the spectral, bidirectional reflectivity. However,measuring the spectral, bidirectional reflectivity of even one point at every set of incident andreflected directions is a time intensive process that is infeasible for quality control.The objective of this work was to determine whether a limited number of spectral, bidirectionalreflectance measurements may be used to characterize the appearance of an opaque surfaceat room temperatures. The results presented in this thesis demonstrate that measurements of thespectral bidirectional reflectivity in the visible spectrum at four sets of specular reflections - 20°,45°, 60°, and 85° - with a resolution of 5 nm may be used to quantify the appearance of an opaquesurface at room temperature. These measurements are converted into parameters called the bidirectionalreflectance appearance parameters (BRAPs). These BRAPs include L*, a*, b* (whichdefine the color of the surface), G20, G60, G85 (which define the gloss of the surface), and H(which describes the haze of the surface). It is shown that surfaces which appear similar havesimilar BRAPs and surfaces which appear different have different BRAPs.

No description available.